Hello,

If you import TA-Lib it will use whatever you pass it as input which can be daily data from the 'history' function. The attached is fairly meaningless but shows the idea.

P.

Thanks. It is a good answer.

But if I switch to daily backtesting mode, history method is no longer working and I have to change the price variable to the ordinary one.
I wonder if there is an one-work-for-all solution to this problem no matter which mode it is like in Multichart.

My guess is probably not, but just wish it maybe exist in Quantopian.

Hi Eric,
I faced the same problem that you are raising. I do not have a solution... what I am doing is the following: I switched to zipline for backtesting (if we work with daily data there are no problems in term of availability of historical data), and for the live test and trading I go with the TWS java API.
This obviously doubles the coding effort (python+zipline, then TWS AAPI+java), but there are a few reasons:
using zipline on my PC I do not have the limitations of the Quantopian IDE, that I find too heavy (namely:
- logs dramatically slow and possibly incomplete (this is the worst thing, as makes very difficult not only the debugging but also the checks on the correctness of the results);
- python with some functionalities not available and not interactive (a dead python, indeed);
- very limited editing functionalities (find and replace, control of the indentation are missing...);
- ...)
I edit the zipline based code with ipython notebook: it is very fast and fully interactive, the unrestricted logs allow an efficient debugging and testing, there are no restictions to the python functionalities.
Yes, there is the recoding to java when moving from the backtests to live test/trading. But this is done only for the algos that are worthy this step ( one out of 10 or more, for me).
In conclusion: many thanks to Quantopian for giving us zipline; for the IDE in my view there still is a lot of work to do (and maybe some rethinking of the design).

@ Leo,

I'm basically thinking along the same lines, having used Quantopian for a long time. A more efficient, flexible way of doing R&D is needed (by me, at least, since I don't have the intuition nor an already-proven algorithm). Where do you get your offline data?

Grant

From yahoo. I used to get the data daily from http://www.eoddata.com, then aggregate them in a mysql database. But this approach requires additional work to handle the splits... with yahoo the problem is already solved, and both python and zipline connect very easily to yahoo.

@Eric,
You can use history with ta-lib for daily indicators, take a look at this example: https://www.quantopian.com/posts/trying-to-understand-this-backtest

One possible point of confusion is that Quantopian has its own ta-lib wrapper. You can use, for example, "ta.ATR" without importing Python's ta-lib module. However, this only runs on certain transformations and is powered by batch_transform. In the future we'd like to optimize this wrapper to integrate with all ta-lib functions and run on history(). Instead of using our built-in ta-lib wrapper, you can directly import Python's ta-lib module and use it like in the example above.

@Leo,
We're making progress! If you're looking for keyboard shortcut tips in the IDE, take a look here. But we're glad that you're finding Zipline useful.